Gas turbine engines often have arrays of airfoils joined to other structures by braze joints that extend along the suction side surface and the pressure side surface of the airfoils. Such joints are typically formed by depositing a braze material into regions where the joint is to be formed, referred to herein as joint regions. The braze material is typically in fluid form and may comprise a mixture of powdered alloy material and binder material. Heat is then applied to cause the braze material to melt and fill the joint regions, wherein upon cooling, the braze material forms the desired joint.
A traditional method for depositing the braze material uses a syringe type applicator filled with braze material. The applicator has a nozzle for dispensing the braze material. The nozzle of the applicator is first guided along the joint region between the suction side of the airfoil and the structure to direct a stream of braze material into such joint region. The nozzle of the applicator is then guided along the joint region between the pressure side of the airfoil and the structure to direct a stream of braze material into the latter joint region. For convenience, streams are sometimes first deposited into the joint regions along the suction sides of an entire array of airfoils, and then streams are deposited into the joint regions along the pressure sides.
The above described method for depositing the braze material has two primary drawbacks. First, the time and the effort required to apply the braze material is approximately twice that required to apply the braze material into the joint region on just one side of the airfoil. Second, the braze material in the joint region on the suction side of the airfoil may harden and thereby form a braze structure prior to the deposition of the braze material in the joint region on the pressure side. Such braze structure does not adhere to the airfoil to the extent that the structure adheres internally. Consequently, nudging of the braze structure, which can occur while depositing braze material along the pressure side of the airfoil, in particular at the leading and/or trailing edge of the airfoil, may displace the braze structure from the joint region to an extent that the braze material from the structure might not flow into the joint region during heating.